1. Field of the Invention
The present invention relates to a hair dryer.
2. Description of the Related Art
When a hair dryer blows air, noise is typically caused by air-column resonance or the like. A technique of reducing noise of a hair dryer is described in, for example, JP-A 1993-228013. A hair dryer utilizing the principle of Helmholtz resonators is described in JP-A 1993-228013. The hair dryer is tubular and contains a motor fitted with a blower fan, and a heater to heat air being blown. The hair dryer includes a case and a resonator. In the case, a plurality of holes are made at positions at which an axial distribution of sound pressure of standing-wave noise due to air-column resonance exhibits high levels. The resonator is attached to cover the holes of the case. That is, a resonance space is defined between the case and the resonator, in other words, inside the hair dryer.
As described above, JP-A 1993-228013 describes a technique of providing the resonator for the plurality of holes to absorb and attenuate sound at specific frequencies to reduce sound pressure.
According to a structure depicted in FIG. 1 of JP-A 1993-228013, however, resonance spaces corresponding to the respective holes are not finely partitioned off. Therefore, noise cannot be reflected inside each of the resonance spaces corresponding to the respective holes, and sufficient effects of noise reduction by Helmholtz resonators cannot be achieved. Meanwhile, according to a structure depicted in FIG. 4 of JP-A 1993-228013, cases to define resonance spaces are provided separately for different sets of holes. Therefore, effects of the Helmholtz resonators may be achieved. However, because the number of cases to define the resonance spaces is increased, the number of parts increases. This results in an increased number of steps of a process of manufacturing the hair dryer, leading to an increased production cost of the hair dryer. Further, an external surface of the hair dryer becomes uneven, spoiling the aesthetic appearance of the hair dryer. Furthermore, a method for ensuring close adhesion of the cases is not disclosed in JP-A 1993-228013.